I read the article you linked to. Looks like it would work if you have the right soil conditions, a lot of time, a lot of help and the patience of Jobe. One concern I would have is if you ran into large rocks or wet soils. We have excavated several buildings over the years using the railroad ties and jacking method followed by a mini excavator. Here in the glacial soils of the northeast, we often run into large boulders that would be impossible to remove without heavy equipment. The other caution would be to pour concrete or an other stable footings for the new post supports. This would be tricky if they are done one at a time as you excavate deeper under the building, especially if building has already settled and is not level at the start. Some level reference would have to be maintained throughout the process. This is not as easy as it may sound, and would require some jacking, sistering of floor joists, or a new set of carrier beams etc. along the way. This vacuum method may be OK for small buildings, but could be troublesome or dangerous for larger buildings or for inexperienced builders. Be careful.
Most crawl spaces are vented if they have an earth floor or are prone to moisture. If you insulate between the floor joists with a moisture, mold and vermin resistant insulation (foam as we discussed before) you would still want some ventilation. The only time I would seal the exterior walls would be if I also used a pretty darn water tight moisture barrier over the floor, tuck taped to the knee wall at the bottom of the joists. You would be creating a dry cell and blocking movement of cold air through and under the house. This is typically done with a rubber/neoprene type compound sheet commercially, but can be done effectively with a couple of layers of good 6 mil poly. This poly is avail at Lowe's, HD, etc. in 10 and 20 foot wide rolls, 25 to 100 foot in length. You can use Tyvek tape to seal the seams and around posts etc. Leave yourself a way to enter the space to check humidity levels occasionally for reassurance.
Your basic plan sounds workable. I assume your crawl space is adjacent to a full basement area? I have a couple of questions. Where does the existing drain tile system empty? Is there a difference in level between existing basement floor and footings of the crawl space? the answers to these questions may change my answer to you. But basically, adding a French drain or perimeter drain tile should help your situation. After your trench is dug, be sure to line it with several inches of gravel/crushed stone. Use perforated pipe with inlet holes or slots on only one half of the surface and be sure the slots are facing up when installed. Wrap the pipe in common landscape cloth before backfilling with crushed stone to prevent the drain pipe from filling with sediment. Lay another layer of cloth over the stone and complete the backfill with clean grave. Not sure how you plan to connect to the basement drain system, but that is another topic. This kind of work is always difficult, especially when working in a crawl space with limited head room. Good luck.
Best Answer
I read the article you linked to. Looks like it would work if you have the right soil conditions, a lot of time, a lot of help and the patience of Jobe. One concern I would have is if you ran into large rocks or wet soils. We have excavated several buildings over the years using the railroad ties and jacking method followed by a mini excavator. Here in the glacial soils of the northeast, we often run into large boulders that would be impossible to remove without heavy equipment. The other caution would be to pour concrete or an other stable footings for the new post supports. This would be tricky if they are done one at a time as you excavate deeper under the building, especially if building has already settled and is not level at the start. Some level reference would have to be maintained throughout the process. This is not as easy as it may sound, and would require some jacking, sistering of floor joists, or a new set of carrier beams etc. along the way. This vacuum method may be OK for small buildings, but could be troublesome or dangerous for larger buildings or for inexperienced builders. Be careful.